[malandrew]

I used to always use a 17" macbook pro and it was always very very comfortable moving from it to a 27" display. However, I found that since going from the 17" to a 13", that my level of productivity has increased greatly because I'm now forced to tackle problems that require greater automation and finesse with keyboard only navigation. Given OS X's horrible support for X-windows and the truly useful window managers like XMonad, dwii, dwm, awesome, etc, it's simply not that convenient moving between a 13" and 27" screen. There is too much setup and change to your workflow to make that switch regularly for any programming activity that involves user interfaces (e.g. HTML/CSS) beyond a terminal or ncurses.

[atmosx]

I practically live the last 2 years on a macbok air 13" which I wouldn't switch for any other laptop, even if I'd had to install linux on it. However every time I go home and sit on my 27" iMac I feel blessed although the MBA is 2011 and has much clearer screen. However, as you said, my working and programming environment is setup on the MBA and I can't sync everything I need on the fly to achieve the same workflow on the imac. Hmm, but I if I could choose I'd take the imac any day.